activated charcoal

Charcoal (Activated) is a finely ground encapsulated powder that is
made from wood that has been exposed to very high temperatures in
the absence of air. Charcoal itself has been used over decades for its
known effectiveness in absorbing and expelling intestinal gas.
Charcoal is classified as an "adsorbent" substance, and for this
reason, it's the popular choice among hospitals today for the
treatment of drug over doses and poisonings.

Charcoal (Activated) may also be used for relieving a variety of ailments,
such as indigestion, nausea and vomiting, diarrhea, high cholesterol,
intestinal gas and bloating. Charcoal's ability to adsorb and prevent
substances from dislodging or reabsorbing into the body makes it a
popular choice for detoxifying the liver and kidneys.

Applied topically, Charcoal also may help draw out poisons and toxins
from wounds, skin irritations, as well as insect bites and stings.
Limit the consumption of Charcoal because it will also absorb nutrients.

Activated charcoal is an excellent material for filtering toxic gases. Activated charcoal were used by workers at the WTC site after 9/11. It has also been incorporated into many Japanese cigarette filters. While more than 70% of cigarettes sold in Japan use activated charcoal filters ("charcoal filters"), less than 1% of cigarette products sold in USA have this.
Japan has significantly lower lung cancer rates than the United States.* However, there is no hard evidence to show a direct link between charcoal filters and reduction of lung cancer rates.
Charcoal filters can also modify the taste of cigarettes by absorbing more chemicals. As a result, many consumers in the United States have rejected it.

Currently I am smoking Mild Seven Lights Charcoal Filter, which a friend of mine has given me. And indeed, it tastes like shit. Here are some reasons that I can think of why charcoal filters have gained wide acceptance in Eastern Asia: (a) Consumer education. (b) The government-owned tobacco monopoly, JT (Japan Tobacco), has less to worry about competition or their bottom line. While the Japanese government has more control over what goes into the smokers' lungs, they chose healthier filters for them.

If interested, JT cigarette products are available at street vending machines (no ID required) for smokers on their next visit to the Western pacific.